The ngEHT Analysis Challenges

TL;DR

The ngEHT Analysis Challenges aim to improve imaging and analysis techniques for the next-generation Event Horizon Telescope, focusing on static and dynamic models of black holes like M87* and Sgr A* to enable high-quality movies and variability studies.

Contribution

This work reports on the first two ngEHT Analysis Challenges, demonstrating the capability to reconstruct detailed images and movies of black hole environments using current algorithms.

Findings

High-quality movies of M87* jet structure can be reconstructed.

Near-horizon hourly variability of Sgr A* can be captured.

Current algorithms have areas for improvement.

Abstract

The next-generation Event Horizon Telescope (ngEHT) will be a significant enhancement of the Event Horizon Telescope (EHT) array, with $\sim 10$ new antennas and instrumental upgrades of existing antennas. The increased $uv$-coverage, sensitivity, and frequency coverage allow a wide range of new science opportunities to be explored. The ngEHT Analysis Challenges have been launched to inform development of the ngEHT array design, science objectives, and analysis pathways. For each challenge, synthetic EHT and ngEHT datasets are generated from theoretical source models and released to the challenge participants, who analyze the datasets using image reconstruction and other methods. The submitted analysis results are evaluated with quantitative metrics. In this work, we report on the first two ngEHT Analysis Challenges. These have focused on static and dynamical models of M87* and Sgr A*, and shown that high-quality movies of the extended jet structure of M87* and near-horizon hourly timescale variability of Sgr A* can be reconstructed by the reference ngEHT array in realistic observing conditions, using current analysis algorithms. We identify areas where there is still room for improvement of these algorithms and analysis strategies. Other science cases and arrays will be explored in future challenges.